As is well known the so called rubber dam technique is sometimes used in dental practice in certain procedures, particularly those in which a large number of small instruments, fittings, chemicals or debris are expected to be introduced into the patient's mouth during the procedure. This technique is the standard of care employed during root canal procedures in order to define a treatment area within the mouth which protects the patient and is not contaminated with saliva. A rubber dam is normally applied by punching a hole in the dam immediately prior to use and then slipping the punched hole over the tooth or teeth to be treated. The rubber dam is held in place by special clamps or ligatures.
The perimeter areas of the rubber dam are usually supplied with elastic retention devices that are placed around the ears or the back of the patient's head, often creating discomfort. Further, the act of securing the rubber frequently disturbs the proper positioning of the dam itself and necessitates placing additional holes in the dam membrane to gain access to the desired tooth. Since multiple perforations of the rubber dam tend to defeat its primary purpose as a barrier, the first rubber dam must be discarded and a second dam utilized. Many dentists forego the use of the rubber dam because its use, while very desirable in theory, is often just too bothersome and time consuming in practice.
Examples of previous rubber dams include the device described in U.S. Pat. No. 2,680,908, entitled DENTAL ISOLATOR AND CONE, issued to Daigle on Jun. 15, 1954, in which a frame and sheet is retained in the mouth by the biting action of opposed teeth. U.S. Pat. No. 3,772,790, entitled TOOTH ISOLATING SHIELD, issued to Swan-Gett on Nov. 20, 1973, discloses a tooth isolating shield having an apron of a deformable material and semirigid dentition bridge conforming members. The Swan-Gett device suffers from the common drawback of requiring that it be tailored to conform to the individual patient's mouth.
The use of an inflatable frame is disclosed in U.S. Pat. No. 3,781,994, entitled ARRANGEMENT FOR SEPARATING AN AREA OF OPERATION OR TREATMENT IN THE ORAL CAVITY, issued to Hesselgren on Jan. 1, 1974. The Hesselgren device utilizes a frame that must be inflated by compressed air in order to stretch the rubber dam into a bowl or funnel shape. U.S. Pat. No. 4,600,387, entitled RUBBER DAM FRAME FOR DENTAL WORK discloses a rubber dam in which a portion of the frame actually resides within the patient's oral cavity, causing substantial discomfort. Further, the resilient rubber sheet must be placed on frame by the dentist at the time of use. Finally, U.S. Pat. No. 4,828,491, entitled UNITARY PREASSEMBLED DISPOSABLE INTRA-ORAL RUBBER DAM DEVICE, issued to Gray on May 9, 1989, also discloses a rubber dam in which the frame is placed within the oral cavity and is retained in place by the force of its resilient frame pressing against the inside of the patient's mouth. The Gray device can potentially obstruct the patient's airway.
In summary, previous attempts to produce a practical rubber dam device have resulted in structures which are awkward to assemble and position as well as uncomfortable for the patient to endure during a lengthy procedure. In addition, the lack of compact dimensions fitting outside of the lips sometimes intimidates fearful patients. This can result in panic attacks and the false perception by the patient that their airway is obstructed. The result is that many dentists have abandoned their use despite the obvious safety advantages offered by rubber dam technology.